Preventing a single student programmer from choking the whole server.

[guy keren]

how about using cgroups, putting each user's login shell in a cgroup 
that cannot use more then X% of the whole CPUs. this will affect all 
processes spawned under the user's shell.

--guy

On 04/21/2017 03:07 PM, Josh Roden wrote:
> Hi
>
> server setup:
> ------------------
> Centos 6
> 32GB RAM
> 16 Cpu's
> 70 students max
>
> I am using /etc/security/limits.conf to prevent the students from
> choking the whole
> server but sometimes one student will write a very bad program that somehow
> runs itself again and again - so fast that "killall" and "pkill -9 -u"
> can't stop/remove
> the user fast enough before the student's program is run again and again...
>
> Here is my definition in limits:
>
>  @stud           hard    cpu             8
>  @stud           hard    nproc           256
>  @stud           hard    nofile          1024
>  @stud           -       maxlogins       6
>
> I can't reduce cpu time below 8min because eclipse will be killed every
> hour or so.
> My problem seems to be that the student can run up to 256 processes that
> each
> uses 100% of a single CPU and we only have 16 CPU''s.
>
> Thanks for any suggestions.
> Josh
>
>
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